The wrong baseline will
do more damage to peak areas, or band areas, than any other single factor. You can get
the peak shape wrong, you can get the peak position wrong, you can get the
peak width wrong, and still not noticeably affect the peak areas. But if
you get the baseline wrong, you may as well throw away your data.

Removing baseline features from a spectrum, without damaging the data, is a
difficult problem.We approach it in the following manner: Our
peak-picker (arguably the world's best) can find the peaks in the data and
estimate their widths. Where the peaks aren't, the baseline is obvious.
Where a peak is, the baseline must run underneath the peak without
intersecting it. We assume the baseline is smooth, and nearly straight in
this region. How well does it work? See Fig 1 below.